text: /* See LICENSE file for copyright and license details. */
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <X11/Xlib.h>
  #include <X11/Xft/Xft.h>
  
  #include "../inc/srw.h"
  #include "../inc/util.h"
  
  #define UTF_INVALID 0xFFFD
  #define UTF_SIZ     4
  
  static const unsigned char utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
  static const unsigned char utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
  static const long utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
  static const long utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
  
  static long
  utf8decodebyte(const char c, size_t *i)
  {
  	for (*i = 0; *i < (UTF_SIZ + 1); ++(*i))
  		if (((unsigned char)c & utfmask[*i]) == utfbyte[*i])
  			return (unsigned char)c & ~utfmask[*i];
  	return 0;
  }
  
  static size_t
  utf8validate(long *u, size_t i)
  {
  	if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
  		*u = UTF_INVALID;
  	for (i = 1; *u > utfmax[i]; ++i)
  		;
  	return i;
  }
  
  static size_t
  utf8decode(const char *c, long *u, size_t clen)
  {
  	size_t i, j, len, type;
  	long udecoded;
  
  	*u = UTF_INVALID;
  	if (!clen)
  		return 0;
  	udecoded = utf8decodebyte(c[0], &len);
  	if (!BETWEEN(len, 1, UTF_SIZ))
  		return 1;
  	for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
  		udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
  		if (type)
  			return j;
  	}
  	if (j < len)
  		return 0;
  	*u = udecoded;
  	utf8validate(u, len);
  
  	return len;
  }
  
  Drw *
  drw_create(Display *dpy, int screen, Window root, unsigned int w, unsigned int h)
  {
  	Drw *drw;
  
  	drw = ecalloc(1, sizeof(Drw));
  	drw->dpy = dpy;
  	drw->screen = screen;
  	drw->root = root;
  	drw->w = w;
  	drw->h = h;
  	drw->drawable = XCreatePixmap(dpy, root, w, h, DefaultDepth(dpy, screen));
  	drw->gc = XCreateGC(dpy, root, 0, NULL);
  	drw->fontcount = 0;
  	XSetLineAttributes(dpy, drw->gc, 1, LineSolid, CapButt, JoinMiter);
  
  	return drw;
  }
  
  void
  drw_resize(Drw *drw, unsigned int w, unsigned int h)
  {
  	drw->w = w;
  	drw->h = h;
  	if (drw->drawable)
  		XFreePixmap(drw->dpy, drw->drawable);
  	drw->drawable = XCreatePixmap(drw->dpy, drw->root, w, h, DefaultDepth(drw->dpy, drw->screen));
  }
  
  void
  drw_free(Drw *drw)
  {
  	size_t i;
  
  	for (i = 0; i < drw->fontcount; i++)
  		drw_font_free(drw->fonts[i]);
  	XFreePixmap(drw->dpy, drw->drawable);
  	XFreeGC(drw->dpy, drw->gc);
  	free(drw);
  }
  
  /* This function is an implementation detail. Library users should use
   * drw_font_create instead.
   */
  static Fnt *
  drw_font_xcreate(Drw *drw, const char *fontname, FcPattern *fontpattern)
  {
  	Fnt *font;
  	XftFont *xfont = NULL;
  	FcPattern *pattern = NULL;
  
  	if (fontname) {
  		/* Using the pattern found at font->xfont->pattern does not yield same
  		 * the same substitution results as using the pattern returned by
  		 * FcNameParse; using the latter results in the desired fallback
  		 * behaviour whereas the former just results in
  		 * missing-character-rectangles being drawn, at least with some fonts.
  		 */
  		if (!(xfont = XftFontOpenName(drw->dpy, drw->screen, fontname))) {
  			fprintf(stderr, "error, cannot load font: '%s'\n", fontname);
  			return NULL;
  		}
  		if (!(pattern = FcNameParse((FcChar8 *) fontname))) {
  			fprintf(stderr, "error, cannot load font: '%s'\n", fontname);
  			XftFontClose(drw->dpy, xfont);
  			return NULL;
  		}
  	} else if (fontpattern) {
  		if (!(xfont = XftFontOpenPattern(drw->dpy, fontpattern))) {
  			fprintf(stderr, "error, cannot load font pattern.\n");
  			return NULL;
  		}
  	} else {
  		die("no font specified.\n");
  	}
  
  	font = ecalloc(1, sizeof(Fnt));
  	font->xfont = xfont;
  	font->pattern = pattern;
  	font->ascent = xfont->ascent;
  	font->descent = xfont->descent;
  	font->h = font->ascent + font->descent;
  	font->dpy = drw->dpy;
  
  	return font;
  }
  
  Fnt*
  drw_font_create(Drw *drw, const char *fontname)
  {
  	return drw_font_xcreate(drw, fontname, NULL);
  }
  
  void
  drw_load_fonts(Drw* drw, const char *fonts[], size_t fontcount)
  {
  	size_t i;
  	Fnt *font;
  
  	for (i = 0; i < fontcount; i++) {
  		if (drw->fontcount >= DRW_FONT_CACHE_SIZE) {
  			die("font cache exhausted.\n");
  		} else if ((font = drw_font_xcreate(drw, fonts[i], NULL))) {
  			drw->fonts[drw->fontcount++] = font;
  		}
  	}
  }
  
  void
  drw_font_free(Fnt *font)
  {
  	if (!font)
  		return;
  	if (font->pattern)
  		FcPatternDestroy(font->pattern);
  	XftFontClose(font->dpy, font->xfont);
  	free(font);
  }
  
  Clr *
  drw_clr_create(Drw *drw, const char *clrname)
  {
  	Clr *clr;
  
  	clr = ecalloc(1, sizeof(Clr));
  	if (!XftColorAllocName(drw->dpy, DefaultVisual(drw->dpy, drw->screen),
  	                       DefaultColormap(drw->dpy, drw->screen),
  	                       clrname, &clr->rgb))
  		die("error, cannot allocate color '%s'\n", clrname);
  	clr->pix = clr->rgb.pixel;
  
  	return clr;
  }
  
  void
  drw_clr_free(Clr *clr)
  {
  	free(clr);
  }
  
  void
  drw_setscheme(Drw *drw, ClrScheme *scheme)
  {
  	drw->scheme = scheme;
  }
  
  
  int
  drw_get_width(Drw *drw, int numcolors, const char *text)
  {
  	Fnt *curfont = drw->fonts[0];
  	int w = drw_text(drw, 0, 0, 0, 0, text, 0) + curfont->h;
  
  	for (unsigned int i = 0; i < strlen(text); i++) {
  		if (text[i] > 0 && text[i] <= numcolors) {
  			/* we found a color code
  			 * drw_text counted it as a normal character and added one character's width
  			 * we aren't going to render this character, so we remove one character's width */
  			w -= curfont->xfont->max_advance_width;
  
  			if (i == 0 || i + 1 == strlen(text)) {
  				/* we're on the first or the last character of the string
  				 * drw_text already added one character's height (divided by 2) as padding to the beginning and end
  				 * we don't want to double this padding, so we skip this character */
  				continue;
  			}
  
  			if (text[i - 1] > 0 && text[i - 1] <= numcolors) {
  				/* the previous character was also a color code
  				 * we already added padding in the previous iteration
  				 * we don't want to double this padding, so we skip this character */
  				continue;
  			}
  
  			/* we are somewhere in the middle of the string and the color has changed
  			 * we want to add one character's height (divided by 2) as padding to the end of the previous colored text
  			 * and to the beginning of the new colored text */
  			w += curfont->h;
  		}
  	}
  
    return w;
  }
  
  void
  drw_colored_text(Drw *drw, ClrScheme *scheme, int numcolors, int x, int y, unsigned int w, unsigned int h, char *text)
  {
  	if (!drw || !drw->fontcount || !drw->scheme)
  		return;
  
  	char *buf = text, *ptr = buf, c = 1;
  	int i;
  
  	while (*ptr) {
  		for (i = 0; *ptr < 0 || *ptr > numcolors; i++, ptr++);
  		if (!*ptr)
  			break;
  		c = *ptr;
  		*ptr = 0;
  		if (i)
  			x = drw_text(drw, x, y, w, h, buf, 0) + drw->fonts[0]->h;
  		*ptr = c;
  		drw_setscheme(drw, &scheme[c-1]);
  		buf = ++ptr;
  	}
  	drw_text(drw, x, y, w, h, buf, 0);
  }
  
  
  
  void
  drw_rect(Drw *drw, int x, int y, unsigned int w, unsigned int h, int filled, int empty, int invert)
  {
  	if (!drw->scheme)
  		return;
  	XSetForeground(drw->dpy, drw->gc, invert ? drw->scheme->bg->pix : drw->scheme->fg->pix);
  	if (filled)
  		XFillRectangle(drw->dpy, drw->drawable, drw->gc, x, y, w + 1, h + 1);
  	else if (empty)
  		XDrawRectangle(drw->dpy, drw->drawable, drw->gc, x, y, w, h);
  }
  
  int
  drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, const char *text, int invert)
  {
  	char buf[1024];
  	int tx, ty, th;
  	Extnts tex;
  	XftDraw *d = NULL;
  	Fnt *curfont, *nextfont;
  	size_t i, len;
  	int utf8strlen, utf8charlen, render;
  	long utf8codepoint = 0;
  	const char *utf8str;
  	FcCharSet *fccharset;
  	FcPattern *fcpattern;
  	FcPattern *match;
  	XftResult result;
  	int charexists = 0;
  
  	if (!drw->scheme || !drw->fontcount)
  		return 0;
  
  	if (!(render = x || y || w || h)) {
  		w = ~w;
  	} else {
  		XSetForeground(drw->dpy, drw->gc, invert ?
  		               drw->scheme->fg->pix : drw->scheme->bg->pix);
  		XFillRectangle(drw->dpy, drw->drawable, drw->gc, x, y, w, h);
  		d = XftDrawCreate(drw->dpy, drw->drawable,
  		                  DefaultVisual(drw->dpy, drw->screen),
  		                  DefaultColormap(drw->dpy, drw->screen));
  	}
  
  	curfont = drw->fonts[0];
  	while (1) {
  		utf8strlen = 0;
  		utf8str = text;
  		nextfont = NULL;
  		while (*text) {
  			utf8charlen = utf8decode(text, &utf8codepoint, UTF_SIZ);
  			for (i = 0; i < drw->fontcount; i++) {
  				charexists = charexists || XftCharExists(drw->dpy, drw->fonts[i]->xfont, utf8codepoint);
  				if (charexists) {
  					if (drw->fonts[i] == curfont) {
  						utf8strlen += utf8charlen;
  						text += utf8charlen;
  					} else {
  						nextfont = drw->fonts[i];
  					}
  					break;
  				}
  			}
  
  			if (!charexists || (nextfont && nextfont != curfont))
  				break;
  			else
  				charexists = 0;
  		}
  
  		if (utf8strlen) {
  			drw_font_getexts(curfont, utf8str, utf8strlen, &tex);
  			/* shorten text if necessary */
  			for (len = MIN((unsigned long)utf8strlen, (sizeof buf) - 1); len && (tex.w > w - drw->fonts[0]->h || w < drw->fonts[0]->h); len--)
  				drw_font_getexts(curfont, utf8str, len, &tex);
  
  			if (len) {
  				memcpy(buf, utf8str, len);
  				buf[len] = '\0';
  				if (len < ((unsigned long)utf8strlen))
  					for (i = len; i && i > len - 3; buf[--i] = '.');
  
  				if (render) {
  					th = curfont->ascent + curfont->descent;
  					ty = y + (h / 2) - (th / 2) + curfont->ascent;
  					tx = x + (h / 2);
  					XftDrawStringUtf8(d, invert ? &drw->scheme->bg->rgb : &drw->scheme->fg->rgb, curfont->xfont, tx, ty, (XftChar8 *)buf, len);
  				}
  				x += tex.w;
  				w -= tex.w;
  			}
  		}
  
  		if (!*text) {
  			break;
  		} else if (nextfont) {
  			charexists = 0;
  			curfont = nextfont;
  		} else {
  			/* Regardless of whether or not a fallback font is found, the
  			 * character must be drawn.
  			 */
  			charexists = 1;
  
  			if (drw->fontcount >= DRW_FONT_CACHE_SIZE)
  				continue;
  
  			fccharset = FcCharSetCreate();
  			FcCharSetAddChar(fccharset, utf8codepoint);
  
  			if (!drw->fonts[0]->pattern) {
  				/* Refer to the comment in drw_font_xcreate for more
  				 * information. */
  				die("the first font in the cache must be loaded from a font string.\n");
  			}
  
  			fcpattern = FcPatternDuplicate(drw->fonts[0]->pattern);
  			FcPatternAddCharSet(fcpattern, FC_CHARSET, fccharset);
  			FcPatternAddBool(fcpattern, FC_SCALABLE, FcTrue);
  
  			FcConfigSubstitute(NULL, fcpattern, FcMatchPattern);
  			FcDefaultSubstitute(fcpattern);
  			match = XftFontMatch(drw->dpy, drw->screen, fcpattern, &result);
  
  			FcCharSetDestroy(fccharset);
  			FcPatternDestroy(fcpattern);
  
  			if (match) {
  				curfont = drw_font_xcreate(drw, NULL, match);
  				if (curfont && XftCharExists(drw->dpy, curfont->xfont, utf8codepoint)) {
  					drw->fonts[drw->fontcount++] = curfont;
  				} else {
  					drw_font_free(curfont);
  					curfont = drw->fonts[0];
  				}
  			}
  		}
  	}
  	if (d)
  		XftDrawDestroy(d);
  
  	return x;
  }
  
  void
  drw_map(Drw *drw, Window win, int x, int y, unsigned int w, unsigned int h)
  {
  	XCopyArea(drw->dpy, drw->drawable, win, drw->gc, x, y, w, h, x, y);
  	XSync(drw->dpy, False);
  }
  
  void
  drw_font_getexts(Fnt *font, const char *text, unsigned int len, Extnts *tex)
  {
  	XGlyphInfo ext;
  
  	XftTextExtentsUtf8(font->dpy, font->xfont, (XftChar8 *)text, len, &ext);
  	tex->h = font->h;
  	tex->w = ext.xOff;
  }
  
  unsigned int
  drw_font_getexts_width(Fnt *font, const char *text, unsigned int len)
  {
  	Extnts tex;
  
  	drw_font_getexts(font, text, len, &tex);
  
  	return tex.w;
  }
  
  Cur *
  drw_cur_create(Drw *drw, int shape)
  {
  	Cur *cur;
  
  	cur = ecalloc(1, sizeof(Cur));
  	cur->cursor = XCreateFontCursor(drw->dpy, shape);
  
  	return cur;
  }
  
  void
  drw_cur_free(Drw *drw, Cur *cursor)
  {
  	if (!cursor)
  		return;
  	XFreeCursor(drw->dpy, cursor->cursor);
  	free(cursor);
  }
  